New York's massively successful High Line has spawned several similar projects around the globe, but an even more unusual park could now be coming to the Big Apple. Following years of planning, the underground Lowline park has finally received a conditional thumbs-up from officials.

Assuming it actually does get built, the Lowline will take up roughly 60,000 sq ft (5,574 sq m) of space in an underground site formerly home to the Williamsburg Bridge Trolley Terminal, in Manhattan's Lower East Side.

Though the idea of an underground park sounds a little drab and depressing, the designers have come up with a system to reflect sunlight down to the park using mirrors and fiber-optic cables. Whether it will be quite the same experience as walking through an above ground park seems doubtful, but it could be interesting in its own right, especially if there's a good selection of plants and trees.

In order to move forward with the project, the Lowline team must now raise US$10 million and draw up detailed schematic designs within a year, in addition to implementing a community engagement plan.

So there's a long road ahead, but the news represents a significant step forward in the realization of what the Lowline team reckons will be the world's first underground park.

Sources: Lowline, NYEDC